1. Technical Field
The present disclosure relates to an optical image capturing system. More particularly, the present disclosure relates to a compact optical image capturing system applicable to electronic products and three-dimensional (3D) image applications thereof.
2. Description of Related Art
In recent years, with the popularity of mobile products with camera functionalities, the demand for a miniaturized optical lens assembly is increasing. The sensor of a conventional photographing camera is typically a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) sensor. As advanced semiconductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact optical lens assemblies have gradually evolved toward the field of higher megapixels, there is an increasing demand for optical lens assemblies featuring better image quality.
A conventional compact optical lens assembly employed in a portable electronic product mainly adopts a four-element lens structure such as the one disclosed in U.S. Pat. No. 7,869,142. Due to the popularity of mobile products with high-end specifications, such as smart phones and PDAs (Personal Digital Assistants), the pixel and image-quality requirements of the compact optical lens assembly have increased rapidly. However, the conventional four-element lens structure cannot satisfy the requirements of the compact optical lens assembly with high-end specifications.
Another conventional optical lens assembly with five-element lens structure such as the one disclosed in U.S. Pat. No. 7,911,711 which provides better image quality and higher resolution. However, since the lens element adjacent to the object side has stronger refractive power, and the lens element adjacent to the image side has weaker refractive power, a larger refraction angle is apt to be generated when the incident light enters the optical lens assembly. More stray light of the optical lens assembly is thereby generated. Besides, the surface design of this optical lens assembly results in excessive astigmatism at the peripheral region and the asymmetry of the optical lens assembly. Thus, the image brightness of the optical lens assembly is reduced and the image quality of the optical lens assembly is constrained.